tests/ftests: synchronize between github runners

tests/ftests: synchronize between github runners

If a VM is shared between multiple github runners, there are chances of
each other stomping over other's run, if executed parallelly.  To avoid
the race between the runners, introduce lock file, that gets acquired
(created) when ftest.sh starts and get removed by ftest-nocontainer.sh,
this ensures that both test cases are executed before other runner,
that's waiting for its chance to run.  A runner would wait for
10 minutes before re-trying to run.  At the max, a runner would wait for
50 minutes (5 retries) before giving up.

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>